Titebond II rolled on to both surfaces and left a few hours to dry. Then used a clothes iron to reactivate the glue. I like that method because that glue is pretty cheap, clean up with water, and there is no smell.
The seam didn’t turn out good enough to leave it as is. So I will dado a slot to receive a piece of mahogany inlay.
I took these outside and flush trimmed the over hanging veneer on the tops and bottoms. I noticed when moving them around I could hear that the kitty litter had settled a bit 
So now they are down on my work bench with a couple of old buyout Peerless of India 5.25" drivers tacked to their tops and humming along nicely at 60 Hz via my variac and step down transformer “driver break in rig”. That should aid in the settling. I’m going to add as much pool filter sand as necessary to completely pack them solid.
Just a thought, maybe adding a drivers to the cab and running some lowish sine waves or music through them would help the litter and sand settle?
Edit: I should really drink less during the day and read more. Please continue. 
When I make seams using the glue and iron method I end up with a gap when I just over lap the veneer and cut it with a strait edge and utility knife. It’s fine until you iron it down. I think the heat of the iron shrinks things. I leave the ends loose enough that I can put 2 or 3 bamboo skewers or something equivalent under one side before I cut the seam. That gives the veneer a little extra length for when you iron the veneer down. I’d make a practice seam before working on the finished cabinet.
Seam with a gap
Seam without a gap
I just read a post on another forum recently where the person pre-irons the veneer before actually adhering it to the speaker, to pre-shrink it. He puts a sheet of wax paper over it to protect it. I’m going to try this the next time I veneer.
just iron it dry, without the glue? heat pre-shrink. then glue, dry and iron on?
Yes, he just laid it out flat and ironed it with no glue to pre-shrink it. However, his main concern was cracking of raw veneer rather than shrinking creating the seam. Since Craig is using paper backed veneer, it may not be relevant to this build, but I use a little of raw veneer that cracks with the iron method.
I cut a couple of thin (3/16") strips from a leftover piece of 3/4" thick mahogany:
Then I set up my tablesaw blade height to that exact depth minus 0.010". Cutting the two slots on the back sides was pretty straight forward.
I just slathered the slots up with some Titebond II and clamped the strips down into the slots. I’ll snap another picture in an hour or so when I take the clamps off. The strips sit just proud. Should be super easy to sand them flush.
I flush trimmed the ends off the inlays then sanded them down to flush. They turned out pretty good with just a slight glue line showing. Oh well… all that is on the back. Can’t see it from my listening seat 
Got brave after work today and flush trimmed the veneer to the driver rebates. They need a bit of fine tuning (hand sanding). I’m happy with how they turned out:
Looks like perfect fit, and perfectly flush. Very clean.
That’s tricky. It wouldn’t hurt my feelings if I never veneered a speaker. Probably because I have the stuff to process solid wood, and a buddy with two sawmills.
Looks really good, dude!
Ya’ll and your skills. I’m sitting here barely able to Duratex something.
